the renal system, biology unit 5 Flashcards
revision
the renal system:
where is the kidney located, and what’s it function?
located on either side of the spine at the lowest level of the rib cage.
Excretion of waste products.
Production and secretion
of the hormone erythropoietin, which
stimulates formation of red blood cells.
Production and secretion of renin, an important enzyme in the control of blood pressure
the renal system:
what’s the Water balance and urine output?
Water is excreted mainly through the urinary system, although some is also excreted through expired air, sweat and through faeces.
Water is mainly controlled by the antiduretic hormone released by
the pituitary gland.
The hypothalamus contains nerve cells called osmoreceptors which
detect changes in the osmotic pressure in the blood. Increase in the
pressure causes the release of an antidiuretic hormone, increasing
water reabsorption. This maintenance of osmotic pressure controls the water and sodium balance within the body.
the renal system:
whats the Renal Artery and Vein:
The Renal Artery leads off from the abdominal aorta.
Once the renal artery enters the Kidney, it splits into two main branches, which each then split into
numerous smaller arteries, which deliver blood to different areas of the kidneys.
Once the blood has been processed here, it is sent back through the renal vein to the inferior vena cava and to the right side section of the heart.
whats the function of the ureter?
The ureter is the tube that carries urine from the kidney to the urinary bladder.
the structure is The tube has thick walls composed of a fibrous, a muscular, and a mucus coat, which
are able to contract.
whats the function of the bladder?
Hollow elastic organ that functions as the body’s urine storage tank.
Urine produced by the kidneys flows through the ureters to the urinary bladder, where is it stored before passing into the urethra and exiting the body.
The urinary bladder plays an important role in delaying and controlling urination.
whats the function of the Urethra?
A tube that connects the urinary bladder to the outside of the body.
The external urethral sphincter is a striated muscle that allows voluntary control over urination.
what is a nephron?
Nephrons are small subunits that make up the kidney.
what is Ultrafiltration?
The blood enters the kidney through the RENAL ARTERY. It enters the GLOMERULUS – a tiny
knot of capillaries.
what happens with Ultrafiltration and the Glomerulus?
The glomerulus receives blood from the afferent arteriole and the blood leaves through the efferent arteriole.
The afferent are wider so the difference in diameter increases the pressure in the blood capillaries of the glomerulus and pushes fluid out
of the capillaries and into the Bowman’s capsule.
what is Bowmans capsule?
the blood goes from artery to glomerulus, it creates extremely high pressure.
This forces everything small enough to leave the blood and enter the first part of the nephron; Bowman’s Capsule.
what is the First Coiled Tubule?
After the filtrate trickles down from Bowman’s Capsule, it contains water, salts, urea, glucose, any hormones and drugs.
However, the body needs to reabsorb the useful products back into the blood.
The first coiled tubule is the first section of the nephron, near the Bowman’s capsule. It is long and coiled.
In the first coiled tubule, glucose is reabsorbed into the capillaries surrounding the nephron.
what is the Loop of Henle?
The ascending limb, which is
impermeable to water, actively pumps chloride ions out of the filtrate into the surrounding fluid.
The descending limb is permeable to
water and impermeable to solutes.
Water is drawn out of the descending
limb by the concentration gradient, so the contents inside become more
concentrated.
The fluid passing onto the ascending limb is therefore more concentrated so more chlorine ions are pumped out and more water is drawn out.
what is Second Coiled Tubule?
This is the third section of the nephron. It is another coiled tubule.
Anything else that needs reabsorbing will be reabsorbed here.
what is the collecting duct?
All the leftover substances end up in the collecting duct.
This includes urea, excess water and salts, any drugs and other waste products from the body’s chemical
reactions.
If the body gets dehydrated, water gets absorbed from the collecting duct.
This leftover waste liquid is known as URINE.
what is ADH?
Anti-diuretic hormone is produced by the pituitary gland in
the brain.
Changes in water levels in the blood are detected by the HYPOTHALAMUS in the brain. It controls release of ADH by the pituitary.
